Bicycle hub unit and bicycle wheel assembly

ABSTRACT

To provide a bicycle hub unit and a bicycle wheel assembly that allow a wheel unit to be appropriately coupled to a hub body, a bicycle hub unit is coupled to a rotary body to which a brake is applied by a brake device. The bicycle hub unit includes a hub body that rotates around a hub axle and a rotary body coupling portion that couples the rotary body to the hub body. The hub body includes a first joint portion and a second joint portion. The first joint portion includes an external thread coupled to an internal thread of the wheel unit. The second joint portion is coupled to a restriction member that restricts relative rotation of the first joint portion and the wheel unit.

BACKGROUND ART

The present invention relates to a bicycle hub unit and a bicycle wheelassembly.

A known bicycle hub unit is coupled to a rotary body to which a brake isapplied by a brake device. A prior art bicycle hub unit includes a hubaxle, which is coupled to a frame of a bicycle, and a hub body, which iscoupled to a wheel unit of the bicycle and rotates around the hub axle.One example of a brake device is a roller brake device. Patent document1 discloses one example of a prior art bicycle hub unit.

Patent Document 1: Japanese Laid-Open Patent Publication No. 2007-62718

SUMMARY OF THE INVENTION

It is preferred that a wheel unit be appropriately coupled to a hubbody.

It is an object of the present invention to provide a bicycle hub unitand a bicycle wheel assembly that allow a wheel unit to be appropriatelycoupled to a hub body.

In accordance with a first aspect of the present invention, a bicyclehub unit is coupled to a rotary body to which a brake is applied by abrake device. The bicycle hub unit includes a hub body that rotatesaround a hub axle and a rotary body coupling portion that couples therotary body to the hub body. The hub body includes a first joint portionand a second joint portion. The first joint portion includes an externalthread coupled to an internal thread of a wheel unit. The second jointportion is coupled to a restriction member that restricts relativerotation of the first joint portion and the wheel unit.

The restriction member restricts relative rotation of the first jointportion and the wheel unit. This limits loosening of the internal threadof the wheel unit with respect to the external thread of the first jointportion. Thus, the wheel unit is appropriately coupled to the hub body.

In accordance with a second aspect of the present invention, the bicyclehub unit according to the first aspect is configured so that the secondjoint portion is arranged on an outer circumference of the hub body.

Thus, the configuration of the second joint portion is simplified.

In accordance with a third aspect of the present invention, the bicyclehub unit according to the second aspect is configured so that the secondjoint portion includes an external thread coupled to an internal threadof the restriction member.

Thus, the configuration of the second joint portion is simplified.

In accordance with a fourth aspect of the present invention, the bicyclehub unit according to the third aspect is configured so that theexternal thread of the second joint portion differs in shape from theexternal thread of the first joint portion.

Thus, the restriction member appropriately restricts relative rotationof the first joint portion and the wheel unit.

In accordance with a fifth aspect of the present invention, the bicyclehub unit according to the fourth aspect is configured so that theexternal thread of the second joint portion differs in pitch from theexternal thread of the first joint portion.

In a direction extending along the center axis of the hub body, amovement amount of the wheel unit corresponding to rotation of the wheelunit with respect to the first joint portion differs from a movementamount of the restriction member corresponding to rotation of therestriction member with respect to the second joint portion. Thus, evenin a case where force generated by the rotation of the wheel unitrelative to the first joint portion is applied to the restrictionmember, the restriction member resists rotating relative to the secondjoint portion. With the bicycle hub unit according to the fifth aspect,the restriction member appropriately restricts relative rotation of thefirst joint portion and the wheel unit.

In accordance with a sixth aspect of the present invention, the bicyclehub unit according to the fifth aspect is configured so that theexternal thread of the second joint portion has a shorter pitch than theexternal thread of the first joint portion.

The restriction member appropriately restricts relative rotation of thefirst joint portion and the wheel unit. Thus, the wheel unit isappropriately coupled to the hub body.

In accordance with a seventh aspect of the present invention, thebicycle hub unit according to any one of the fourth to sixth aspects isconfigured so that the external thread of the second joint portion andthe external thread of the first joint portion are wound in oppositedirections.

In a direction extending along the center axis of the hub body, amovement direction of the wheel unit corresponding to rotation of thewheel unit relative to the first joint portion differs from a movementdirection of the restriction member corresponding to rotation of therestriction member relative to the second joint portion. Thus, even in acase where force generated by the rotation of the wheel unit relative tothe first joint portion is applied to the restriction member, therestriction member resists rotating relative to the second jointportion. With the bicycle hub unit according to the seventh aspect, therestriction member appropriately restricts relative rotation of thefirst joint portion and the wheel unit.

In accordance with an eighth aspect of the present invention, thebicycle hub unit according to the seventh aspect is configured so thatthe winding direction of the external thread of the first joint portionis right-handed, and the winding direction of the external thread of thesecond joint portion is left-handed.

The restriction member appropriately restricts relative rotation of thefirst joint portion and the wheel unit. Thus, the wheel unit isappropriately coupled to the hub body.

In accordance with a ninth aspect of the present invention, the bicyclehub unit according to any one of the third to eighth aspects isconfigured so that in a direction extending along a center axis of thehub body, a range in which the external thread of the first jointportion is arranged is wider than a range in which the external threadof the second joint portion is arranged.

Thus, the wheel unit is appropriately coupled to the hub body.

In accordance with a tenth aspect of the present invention, the bicyclehub unit according to any one of the second to ninth aspects isconfigured so that the hub body further includes a large diameterportion and a small diameter portion, and the second joint portion isarranged on an outer circumference of the small diameter portion.

Thus, the hub body and the restriction member are reduced in size.

In accordance with an eleventh aspect of the present invention, thebicycle hub unit according to the tenth aspect is configured so that thefirst joint portion is arranged on an outer circumference of the largediameter portion.

Thus, the wheel unit is easily coupled to the first joint portion.

In accordance with a twelfth aspect of the present invention, thebicycle hub unit according to the eleventh aspect is configured so thatthe large diameter portion has a smaller outer diameter than therestriction member.

Thus, the restriction member appropriately restricts relative rotationof the first joint portion and the wheel unit.

In accordance with a thirteenth aspect of the present invention, thebicycle hub unit according to the eleventh or twelfth aspects isconfigured so that the large diameter portion includes a first largediameter end located toward the small diameter portion, a second largediameter end opposite to the first large diameter end, a first largediameter portion including the first large diameter end, and a secondlarge diameter portion including the second large diameter end. Thefirst joint portion is arranged on an outer circumference of the firstlarge diameter portion.

Thus, the wheel unit is appropriately coupled to the hub body.

In accordance with a fourteenth aspect of the present invention, thebicycle hub unit according to the thirteenth aspect is configured sothat the second large diameter portion includes a tapered portion. Thetaper portion has an outer diameter that increases at positions awayfrom the first joint portion in a direction extending along a centeraxis of the hub body.

In a direction extending along the center axis of the hub body, therestriction member restricts relative rotation of the wheel unit and thefirst joint portion in one direction, and the tapered portion restrictsrelative rotation of the wheel unit and the first joint portion in theother direction. Thus, the wheel unit is appropriately coupled to thehub body.

In accordance with a fifteenth aspect of the present invention, thebicycle hub unit according to any one of the first to fourteenth aspectsfurther includes a transmission portion that transmits at least humandriving force to the hub body.

Thus, the wheel unit is appropriately coupled to the hub body.

In accordance with a sixteenth aspect of the present invention, thebicycle hub unit according to the fifteenth aspect further includes ashifting mechanism that changes speed of an input from the transmissionportion and transmits the input to the wheel unit.

Thus, the rider can comfortably ride the bicycle.

In accordance with a seventeenth aspect of the present invention, thebicycle hub unit according to the sixteenth aspect is configured so thatthe shifting mechanism is configured to change a transmission ratio ofthe transmission portion and the wheel unit.

Thus, the rider can ride the bicycle at transmission ratios suitable forthe rider.

In accordance with an eighteenth aspect of the present invention, thebicycle hub unit according to the seventeenth aspect is configured sothat the shifting mechanism has at least three transmission ratios ormore.

Thus, the rider can ride the bicycle at transmission ratios suitable forthe rider.

In accordance with a nineteenth aspect of the present invention, thebicycle hub unit according to any one of the sixteenth to eighteenthaspects is configured so that the shifting mechanism is located at aradially inner side of the hub body.

Thus, the shifting mechanism can be arranged inside the hub body.

In accordance with a twentieth aspect of the present invention, thebicycle hub unit according to any one of the first to nineteenth aspectsfurther includes the hub axle.

Thus, the wheel unit is appropriately coupled to the hub body.

In accordance with a twenty-first aspect of the present invention, abicycle wheel assembly includes the bicycle hub unit according to anyone of the first to twentieth aspects, the wheel unit, and therestriction member. The wheel unit includes a hub coupling portioncoupled to the hub body.

The restriction member restricts relative rotation of the first jointportion and the wheel unit. This limits loosening of the internal threadof the hub coupling portion with respect to the external thread of thefirst joint portion. Thus, the wheel unit is appropriately coupled tothe hub body.

In accordance with a twenty-second aspect of the present invention, thebicycle wheel assembly according to the twenty-first aspect isconfigured so that the restriction member includes a nut, and the secondjoint portion includes an external thread coupled to an internal threadof the nut.

Thus, the restriction member is appropriately coupled to the secondjoint portion.

In accordance with a twenty-third aspect of the present invention, thebicycle wheel assembly according to the twenty-second aspect isconfigured so that the hub coupling portion includes a first taperedsurface. The restriction member includes a second tapered surface incontact with the first tapered surface. The first tapered surface has adiameter that decreases toward the restriction member in a directionextending along a center axis of the hub body. The second taperedsurface has a diameter that increases toward the hub coupling portion inthe direction extending along the center axis of the hub body.

The contact of the first tapered surface with the second tapered surfacecauses the hub coupling portion and the restriction member to be forcedagainst the hub body. This restricts rotation of the wheel unit relativeto the hub body. Thus, the wheel unit is appropriately coupled to thehub body.

In accordance with a twenty-fourth aspect of the present invention, thebicycle wheel assembly according to the twenty-third aspect isconfigured so that the hub coupling portion has a center axis that isnot aligned with the center axis of the hub body.

With the restriction member coupled to the second joint portion, thefirst tapered surface is in strong contact with the second taperedsurface. The hub coupling portion and the restriction member arestrongly forced against the hub body. Thus, rotation of the wheel unitrelative to the hub body is appropriately restricted, and the wheel unitis appropriately coupled to the hub body.

In accordance with a twenty-fifth aspect of the present invention, thebicycle wheel assembly according to the twenty-fourth aspect isconfigured so that the restriction member has a center axis that isaligned with the center axis of the hub body.

Thus, rotation of the wheel unit relative to the hub body isappropriately restricted, and the wheel unit is appropriately coupled tothe hub body.

In accordance with a twenty-sixth aspect of the present invention, thebicycle wheel assembly according to any one of the twenty-first totwenty-fifth aspects is configured so that the wheel unit furtherincludes a rim.

Thus, the rim is appropriately coupled to the hub body.

In accordance with a twenty-seventh aspect of the present invention, thebicycle wheel assembly according to the twenty-sixth aspect isconfigured so that a material forming the rim includes at least a resin.

This contributes to weight reduction of the rim.

In accordance with a twenty-eighth aspect of the present invention, thebicycle wheel assembly according to the twenty-sixth or twenty-seventhaspect is configured so that the wheel unit further includes a spokethat connects the rim and the hub coupling portion.

Thus, the spoke is appropriately coupled to the hub body.

In accordance with a twenty-ninth aspect of the present invention, thebicycle wheel assembly according to the twenty-eighth aspect isconfigured so that a material forming the spoke includes at least aresin.

This contributes to weight reduction of the spoke.

In accordance with a thirtieth aspect of the present invention, thebicycle wheel assembly according to the twenty-eighth or twenty-ninthaspect is configured so that the spoke is arranged integrally with atleast one of the hub coupling portion and the rim.

Thus, the number of components in the wheel unit is reduced.

In accordance with a thirty-first aspect of the present invention, thebicycle wheel assembly according to any one of the twenty-first tothirtieth aspects is configured so that a material forming the hubcoupling portion includes at least a resin.

This contributes to weight reduction of the hub coupling portion.

In accordance with a thirty-second aspect of the present invention, thebicycle wheel assembly according to any one of the twenty-first tothirty-first aspects is configured so that the bicycle wheel assembly isa rear wheel.

Thus, the wheel unit of the rear wheel is appropriately coupled to thehub body.

The bicycle hub unit and the bicycle wheel assembly of the presentinvention allow the wheel unit to be appropriately coupled to the hubbody.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a bicycle including a first embodiment of abicycle hub unit.

FIG. 2 is a front view of a bicycle wheel assembly shown in FIG. 1.

FIG. 3 is a cross-sectional view taken along line Z3-Z3 in FIG. 2.

FIG. 4 is an enlarged view of a Z portion shown in FIG. 3.

FIG. 5 is an exploded perspective view of a second embodiment of abicycle wheel assembly.

FIG. 6 is a partially cross-sectional view of a third embodiment of abicycle wheel assembly.

EMBODIMENTS OF THE INVENTION First Embodiment

A bicycle A including a bicycle hub unit 20 will now be described withreference to FIG. 1.

The bicycle A includes the bicycle hub unit 20 (hereafter, referred toas “the hub unit 20”). The type of the bicycle A shown in the drawingsis a city cycle. The type of the bicycle can be a road bike, a mountainbike, a trekking bike, or a cross bike. The bicycle A further includes aframe A1, a front fork A2, a front wheel A3, a rear wheel A4, ahandlebar A5, and a drivetrain B.

The hub unit 20 is provided on at least one of the front wheel A3 andthe rear wheel A4. In one example, the hub unit 20 is provided on therear wheel A4 and the hub unit 20 is arranged on a rear end A6 of theframe A1. A bicycle hub unit 20A (hereafter, referred to as “the hubunit 20A”) provided on the front wheel A3 is arranged on the front forkA2. The hub unit 20A is, for example, the hub unit 20 that does notinclude a shifting mechanism 44 (refer to FIG. 3), which will bedescribed later.

The drivetrain B includes a crank assembly C, a front sprocket D1, arear sprocket D2, and a chain D3. The crank assembly C includes acrankshaft C1, two crank arms C2, and two pedals C3. The two pedals C3are rotatably coupled to the distal ends of the crank arms C2.

The front sprocket D1 is arranged on the crank assembly C to rotateintegrally with the crankshaft C1. The rear sprocket D2 is arranged onthe hub unit 20 of the rear wheel A4. The chain D3 runs around the frontsprocket D1 and the rear sprocket D2. Human driving force applied by therider of the bicycle A to the pedals C3 is transmitted via the frontsprocket D1, the chain D3, and the rear sprocket D2 to the rear wheelA4.

The bicycle A further includes an electric assist unit E. The electricassist unit E operates to assist propulsion of the bicycle A. Theelectric assist unit E operates, for example, in accordance with humandriving force applied to the pedals C3. The electric assist unit Eincludes an electric motor E1. The electric assist unit E is driven byelectric power supplied from a battery BT mounted on the bicycle A. Theelectric assist unit E and the battery BT can be omitted from thebicycle A.

The bicycle A further includes two brake devices F. The brake devices Fare mechanically or electrically driven to apply brakes on rotary bodiesFl (refer to FIG. 3) of the bicycle A in accordance with operation ofoperating devices G. The operating devices G are arranged, for example,on the handlebar A5. One of the brake devices F is arranged on the frontwheel A3. The other one of the brake devices F is arranged on the rearwheel A4. The brake devices F are, for example, hub brake devices inwhich the rotary bodies Fl are directly coupled to the hub units 20 and20A. The brake devices F are, for example, hub brake devices in whichforce applied to the rotary bodies Fl is transmitted to the hub units 20and 20A not via rims 14C. In one example, the brake devices F are rollerbrake devices (refer to FIG. 3). In this example, the rotary bodies Flare brake drums (refer to FIG. 3) respectively arranged on the brakedevices F to be rotatable with respect to the frame A1.

The bicycle A further includes a bicycle wheel assembly 10 (hereafter,referred to as “the wheel assembly 10”). The wheel assembly 10 is therear wheel A4. The wheel assembly 10 includes the hub unit 20. One ofthe rotary bodies F1 to which brakes are applied by the brake devices Fis coupled to the hub unit 20 (refer to FIG. 3).

The wheel assembly 10 further includes a wheel unit 12. The wheel unit12 includes a hub coupling portion 14A (refer to FIG. 2) coupled to thehub unit 20. One of the materials forming the hub coupling portion 14Aincludes at least a resin. The hub coupling portion 14A is coupled tothe hub unit 20, for example, to cover the hub unit 20. The wheel unit12 further includes a rim 14C. One of the materials forming the rim 14Cincludes at least a resin. The wheel unit 12 further includes spokes 14Dconnecting the rim 14C and the hub coupling portion 14A. One of thematerials forming the spokes 14D includes at least a resin. The numberof the spokes 14D is, for example, five. The spokes 14D are arrangedintegrally with at least one of the hub coupling portion 14A and the rim14C. In one example of the wheel unit 12, the hub coupling portion 14A,the rim 14C, and all of the plurality of spokes 14D are arrangedintegrally with each other. A wheel unit 12A coupled to the hub unit 20Aof the front wheel A3 has, for example, the same structure as the wheelunit 12 of the rear wheel A4.

The structure of the hub unit 20 will now be described with reference toFIGS. 2 and 3. FIG. 3 does not show a part of the wheel unit 12.

As shown in FIG. 2, the hub unit 20 includes a hub body 24, whichrotates around a hub axle 22, and a rotary body coupling portion 40(refer to FIG. 3), which couples the rotary body F1 to the hub body 24.In one example, the rotary body F1 is coupled to the rotary bodycoupling portion 40 so that the rotary body F1 is fixed to the rotarybody coupling portion 40 so as to rotate integrally with the hub body 24about a center axis CA1 of the hub body 24. The hub unit 20 furtherincludes the hub axle 22.

The hub body 24 includes a first joint portion 26 and a second jointportion 28. The first joint portion 26 includes an external thread 26Acoupled to an internal thread 16 (refer to FIG. 3) of the wheel unit 12.The second joint portion 28 is coupled to a restriction member 18restricting relative rotation of the first joint portion 26 and thewheel unit 12. The internal thread 16 of the wheel unit 12 is arranged,for example, on the hub coupling portion 14A (refer to FIG. 3). In oneexample, the hub coupling portion 14A is coupled to an outercircumference 24A of the hub body 24. The wheel assembly 10 furtherincludes the restriction member 18.

The hub body 24 further includes a large diameter portion 30 and a smalldiameter portion 38. The large diameter portion 30 and the smalldiameter portion 38 are arranged, for example, integrally with eachother. The large diameter portion 30 has a larger outer diameter thanthe small diameter portion 38. The rotary body coupling portion 40 iscoupled to, for example, the small diameter portion 38 (refer to FIG.3). The large diameter portion 30 includes a first large diameter end32A located toward the small diameter portion 38, a second largediameter end 34A opposite to the first large diameter end 32A, a firstlarge diameter portion 32 including the first large diameter end 32A,and a second large diameter portion 34 including the second largediameter end 34A. The outer circumference 24A of the hub body 24includes an outer circumference 30A of the large diameter portion 30 andan outer circumference 38A of the small diameter portion 38. The outercircumference 30A of the large diameter portion 30 includes an outercircumference 32B of the first large diameter portion 32 and an outercircumference 34B of the second large diameter portion 34. In oneexample, the first large diameter portion 32 and the second largediameter portion 34 are arranged integrally with each other so that theouter circumference 32B of the first large diameter portion 32 iscontinuous with the outer circumference 34B of the second large diameterportion 34.

The first joint portion 26 is arranged on the outer circumference 24A ofthe hub body 24. In one example, the first joint portion 26 is arrangedon the outer circumference 30A of the large diameter portion 30. Morespecifically, the first joint portion 26 is arranged on the outercircumference 32B of the first large diameter portion 32. The internalthread 16 of the wheel unit 12 is arranged, for example, on an innercircumferential surface 14B of the hub coupling portion 14A at a portioncorresponding to the external thread 26A of the first joint portion 26(refer to FIG. 3). In one example, the wheel unit 12 is inserted intothe large diameter portion 30 from the side of the rotary body couplingportion 40 in a direction extending along the center axis CA1 of the hubbody 24, and the internal thread 16 is coupled to the external thread26A. In the example shown in FIG. 2, the winding direction of theexternal thread 26A of the first joint portion 26 is right-handed. Thatis, the external thread 26A of the first joint portion 26 is aright-handed thread.

The second joint portion 28 is arranged on the outer circumference 24Aof the hub body 24. In one example, the second joint portion 28 isarranged on the outer circumference 38A of the small diameter portion38. The second joint portion 28 includes an external thread 28A coupledto an internal thread 18B of the restriction member 18 (refer to FIG.3). In one example, the restriction member 18 is inserted into the smalldiameter portion 38 from the side of the rotary body coupling portion 40in a direction extending along the center axis CA1 of the hub body 24,and the internal thread 18B is coupled to the external thread 28A. Inthe example shown in FIG. 2, the winding direction of the externalthread 28A of the second joint portion 28 is right-handed. That is, theexternal thread 28A of the second joint portion 28 is a right-handedthread. The restriction member 18 includes a nut 18A. The nut 18Aincludes the internal thread 18B. In one example, the internal thread18B of the nut 18A is coupled to the external thread 28A of the secondjoint portion 28. The large diameter portion 30 has a smaller outerdiameter than the restriction member 18.

The second large diameter portion 34 includes a tapered portion 36. Thetapered portion 36 is arranged on the outer circumference 34B of thesecond large diameter portion 34. The tapered portion 36 has an outerdiameter that increases at positions away from the first joint portion26 in a direction extending along the center axis CA1 of the hub body24. Thus, during relative rotation of the first joint portion 26 and thewheel unit 12 about the center axis CA1 of the hub body 24, the taperedportion 36 restricts movement of the wheel unit 12 toward the secondlarge diameter end 34A. The tapered portion 36 can be omitted from thesecond large diameter portion 34.

As shown in FIG. 3, the hub unit 20 further includes a transmissionportion 42 transmitting at least human driving force to the hub body 24.The transmission portion 42 is arranged, for example, on the secondlarge diameter end 34A of the hub body 24. In one example, the rearsprocket D2 is coupled to the transmission portion 42. The transmissionportion 42 transmits driving force received from the rear sprocket D2 tothe hub body 24. The driving force received from the rear sprocket D2includes at least one of human driving force inputted to the rearsprocket D2 via, for example, the pedals C3, and driving force inputtedto the rear sprocket D2 by the electric assist unit E.

The hub unit 20 further includes the shifting mechanism 44 changing thespeed of an input from the transmission portion 42 and transmitting theinput to the wheel unit 12. The shifting mechanism 44 is configured tochange the transmission ratio of the transmission portion 42 and thewheel unit 12. The shifting mechanism 44 is located at a radially innerside of the hub body 24. In one example, the shifting mechanism 44 is aninternal shifting device. The shifting mechanism 44 is mechanically orelectrically driven in accordance with operation of a shift operatingdevice H (refer to FIG. 1). The shift operating device H is arranged,for example, on the handlebar A5. In a case where the shifting mechanism44 is electrically driven, for example, electric power of the battery BTis used. The shifting mechanism 44 includes a planetary gear mechanism.The shifting mechanism 44 is configured to change the transmissionratio, for example, by changing the coupling state of gears forming theplanetary gear mechanism. In one example, the shifting mechanism 44 hasat least three transmission ratios or more.

In a case where driving force input to the transmission portion 42 istransmitted to the hub body 24, the wheel unit 12 rotates together withthe hub body 24 about the center axis CA1 of the hub body 24. In thiscase, the friction received by the wheel unit 12 from the ground (notshown) applies force to the wheel unit 12 so that the wheel unit 12 actsto rotate with respect to the hub body 24 in one direction. In a casewhere the brake device F applies a brake on the rotary body F1 inaccordance with operation of the operating device G, the brake isapplied on the wheel unit 12 in addition to the hub body 24. In thiscase, the friction received by the wheel unit 12 from the ground appliesforce to the wheel unit 12 so that the wheel unit 12 acts to rotate withrespect to the hub body 24 in the other direction. The first jointportion 26 and the second joint portion 28 are configured to restrictrotation of the wheel unit 12 relative to the hub body 24 even in a casewhere the forces described above are applied to the wheel unit 12.

The relationship between the first joint portion 26 and the second jointportion 28 will now be described with reference to FIG. 4.

The external thread 28A of the second joint portion 28 differs in shapefrom the external thread 26A of the first joint portion 26. The externalthread 28A of the second joint portion 28 has a pitch (hereafter,referred to as “the second pitch P2”). The external thread 26A of thefirst joint portion 26 has a pitch (hereafter, referred to as “the firstpitch P1”). The second pitch P2 differs from the first pitch P1. Morespecifically, in a direction extending along the center axis CA1 of thehub body 24, a movement amount corresponding to one rotation of thewheel unit 12 with respect to the first joint portion 26 around the hubaxle 22 differs from a movement amount corresponding to one rotation ofthe restriction member 18 with respect to the second joint portion 28around the hub axle 22. In one example, the second pitch P2 is shorterthan the first pitch P1. The second pitch P2 can be longer than thefirst pitch P1. The difference of the first pitch P1 and the secondpitch P2 limits integral rotation of the wheel unit 12 and therestriction member 18. In other words, the first joint portion 26 andthe second joint portion 28 are configured to restrict integral rotationof the wheel unit 12 and the restriction member 18. Thus, even in a casewhere force is applied to the wheel unit 12 in different rotationaldirections, rotation of the wheel unit 12 relative to the hub body 24 isrestricted.

In the direction extending along the center axis CA1 of the hub body 24,the range in which the external thread 26A of the first joint portion 26is arranged (hereafter, referred to as “the first range R1”) is widerthan the range in which the external thread 28A of the second jointportion 28 is arranged (hereafter, referred to as “the second rangeR2”). The first range R1 can be the same width as the second range R2 orcan be narrower than the second range R2.

Second Embodiment

A second embodiment of a bicycle wheel assembly 210 including a hub unit220 will now be described with reference to FIG. 5. The same referencecharacters are given to those components that are the same as thecorresponding components of the first embodiment. Such components willnot be described in detail. FIG. 5 does not show a part of the wheelunit 12.

A hub body 224 includes a first joint portion 56 and a second jointportion 58. The first joint portion 56 includes an external thread 56Acoupled to an internal thread 52 of the wheel unit 12. The second jointportion 58 is coupled to the restriction member 18, which restrictsrelative rotation of the first joint portion 56 and the wheel unit 12.The first joint portion 56 is arranged, for example, on the outercircumference 32B of the first large diameter portion 32. The internalthread 52 of the wheel unit 12 is arranged, for example, on the innercircumferential surface 14B of the hub coupling portion 14A at a portioncorresponding to the external thread 56A of the first joint portion 56.The second joint portion 58 is arranged, for example, on the outercircumference 38A of the small diameter portion 38. The second jointportion 58 includes an external thread 58A coupled to an internal thread54 of the nut 18A.

The external thread 58A of the second joint portion 58 differs in shapefrom the external thread 56A of the first joint portion 56. The externalthread 58A of the second joint portion 58 differs in the windingdirection from the external thread 56A of the first joint portion 56.The winding direction of the external thread 56A of the first jointportion 56 is, for example, right-handed. That is, the external thread56A of the first joint portion 56 is a right-handed thread. The windingdirection of the external thread 58A of the second joint portion 58 is,for example, left-handed. That is, the external thread 58A of the secondjoint portion 58 is a left-handed thread. In a case where the windingdirection of the external thread 56A of the first joint portion 56 isleft-handed, the winding direction of the external thread 58A of thesecond joint portion 58 can be right-handed. The difference in thewinding direction between the external thread 56A of the first jointportion 56 and the external thread 58A of the second joint portion 58limits integral rotation of the wheel unit 12 and the restriction member18. In other words, the first joint portion 56 and the second jointportion 58 are configured to restrict integral rotation of the wheelunit 12 and the restriction member 18. Thus, even in a case where forceis applied to the wheel unit 12 in different rotation directions,rotation of the wheel unit 12 relative to the hub body 224 isrestricted.

The pitch (hereafter, referred to as “the third pitch”) of the externalthread 56A of the first joint portion 56 and the pitch (hereafter,referred to as “the fourth pitch”) of the external thread 58A of thesecond joint portion 58 have the relationship described below. In afirst example, the fourth pitch is shorter than the third pitch. In asecond example, the fourth pitch is longer than the third pitch. In athird example, the fourth pitch is the same as the third pitch.

Third Embodiment

A third embodiment of a bicycle wheel assembly 310 will now be describedwith reference to FIG. 6. The same reference characters are given tothose components that are the same as the corresponding components ofthe first embodiment. Such components will not be described in detail.

The bicycle A includes the bicycle wheel assembly 310 (hereafter,referred to as “the wheel assembly 310”). The wheel assembly 310 is therear wheel A4. The wheel assembly 310 includes a hub unit 320, a wheelunit 62, and a restriction member 70. The wheel unit 62 includes a hubcoupling portion 64 coupled to a hub body 324. One of the materialsforming the hub coupling portion 64 includes at least a resin. The hubcoupling portion 64 is, for example, coupled to an outer circumference324A of the hub body 324 to cover the hub body 324. The wheel unit 62has substantially the same structure as the wheel unit 12 except for thehub coupling portion 64. In one example, in the wheel unit 62, the hubcoupling portion 64, the rim 14C, and all of the plurality of spokes 14Dare arranged integrally with each other. FIG. 6 does not show a part ofthe wheel unit 62.

The hub body 324 includes a first joint portion 76 and a second jointportion 78. The first joint portion 76 includes an external thread 76Acoupled to an internal thread 68 of the wheel unit 62. The second jointportion 78 is coupled to the restriction member 70, which restrictsrelative rotation of the first joint portion 76 and the wheel unit 62.The first joint portion 76 is arranged, for example, on the outercircumference 32B of the first large diameter portion 32. The internalthread 68 of the wheel unit 62 is arranged, for example, on an innercircumferential surface 64A of the hub coupling portion 64 at a portioncorresponding to the external thread 76A of the first joint portion 76.The second joint portion 78 is arranged, for example, on the outercircumference 38A of the small diameter portion 38. The restrictionmember 70 includes a nut 70A. The second joint portion 78 includes anexternal thread 78A coupled to an internal thread 70B of the nut 70A. Apart of the outer diameter of the small diameter portion 38 is, forexample, the same as the outer diameter of the large diameter portion30. The entire outer diameter of the small diameter portion 38 can besmaller than the outer diameter of the large diameter portion 30. In thepresent embodiment, the external thread 78A of the second joint portion78 and the external thread 76A of the first joint portion 76 areidentical in shape.

The external thread 78A of the second joint portion 78 can differ inshape from the external thread 76A of the first joint portion 76. In afirst example, the pitch of (hereafter, referred to as “the sixthpitch”) of the external thread 78A of the second joint portion 78 isshorter than the pitch (hereafter, referred to as “the fifth pitch) ofthe external thread 76A of the first joint portion 76. In a secondexample, the sixth pitch is longer than the fifth pitch. In a thirdexample, the winding direction of the external thread 76A of the firstjoint portion 76 is right-handed, and the winding direction of theexternal thread 78A of the second joint portion 78 is left-handed. In afourth example, the winding direction of the external thread 76A of thefirst joint portion 76 is left-handed, and the winding direction of theexternal thread 78A of the second joint portion 78 is right-handed. In afifth example, the first joint portion 76 and the second joint portion78 can have a mode combining one of the first and second examples withone of the third and fourth examples.

The hub coupling portion 64 includes a first tapered surface 66. Withthe hub coupling portion 64 coupled to the hub body 324, the firsttapered surface 66 is arranged on the hub coupling portion 64 at aportion facing the restriction member 70. The first tapered surface 66has a diameter that decreases toward the restriction member 70 in thedirection extending along the center axis CA1 of the hub body 324. Thehub coupling portion 64 has a center axis CA2 that is not aligned withthe center axis CA1 of the hub body 324.

The restriction member 70 includes a second tapered surface 72 incontact with the first tapered surface 66. With the restriction member70 coupled to the hub body 324, the second tapered surface 72 isarranged on the restriction member 70 at a portion facing the hubcoupling portion 64. The second tapered surface 72 has a diameter thatincreases toward the hub coupling portion 64 in the direction extendingalong the center axis CA1 of the hub body 324. The restriction member 70has a center axis CA3 aligned with the center axis CA1 of the hub body324. The center axis CA3 of the restriction member 70 can be out ofalignment with the center axis CA1 of the hub body 324. In one example,with the wheel unit 62 and the restriction member 70 appropriatelycoupled to the hub body 324, a part of the first tapered surface 66 isin contact with a part of the second tapered surface 72.

The internal thread 68 of the wheel unit 62 is coupled to the externalthread 76A of the first joint portion 76, and the internal thread 70B ofthe restriction member 70 is coupled to the external thread 78A of thesecond joint portion 78. The internal thread 70B of the restrictionmember 70 is coupled to the external thread 78A of the second jointportion 78 so that the first tapered surface 66 is in strong contactwith the second tapered surface 72. As a result, force in a firstdirection DF1 acts on the hub coupling portion 64, and force in a seconddirection DF2 acts on the restriction member 70. More specifically, at aportion where the first tapered surface 66 is in contact with the secondtapered surface 72, force of the restriction member 70 pushing the hubcoupling portion 64 in the first direction DF1 acts on the hub couplingportion 64. At a portion where the first tapered surface 66 is not incontact with the second tapered surface 72, force acts on therestriction member 70 in the second direction DF2 due to the reactionforce of the first direction DF1. Thus, the hub coupling portion 64 andthe restriction member 70 are forced against the hub body 324, androtation of the wheel unit 62 relative to the hub body 324 isrestricted.

Modified Examples

The description related with each of the above embodiments, without anyintention to limit, exemplifies an applicable form of a bicycle hub unitand a bicycle wheel assembly according to the present invention. Thebicycle hub unit and the bicycle wheel assembly according to the presentinvention are applicable to, for example, modified examples of the aboveembodiments described below and at least two of the modified examplesthat do not contradict each other. In the modified examples describedbelow, the same reference characters are given to those components thatare the same as the corresponding components of the above embodiments.Such components will not be described in detail.

The configurations of the second joint portions 28 and 58 can be changedin any manner. In one example, the second joint portions 28 and 58 arecoupled to the restriction member 18, for example, by adhesion, fusing,or welding.

The configuration of the shifting mechanism 44 can be changed in anymanner. In one example, the shifting mechanism 44 is an externalshifting device. In this example, the drivetrain B includes multiplerear sprockets D2. The shifting mechanism 44 can be omitted from the hubunit 20.

The configurations of the wheel units 12 and 62 can be changed in anymanner. In a first example, the wheel units 12 and 62 are configured sothat at least one of the hub coupling portions 14A and 64, the rim 14C,and the plurality of spokes 14D is separately arranged. In a secondexample, the material forming the hub coupling portions 14A and 64 doesnot include resin. In this example, the material forming the hubcoupling portions 14A and 64 is, for example, metal. In a third example,the material forming the rim 14C does not include resin. In thisexample, the material forming the rim 14C is, for example, metal. In afourth example, the material forming the spokes 14D does not includeresin. In this example, the material forming the spokes 14D is, forexample, metal.

The brake devices F can be changed to any type. In a first example, thebrake devices F are disc brake devices. A disc brake device is oneexample of a hub brake. In this example, the rotary bodies F1 are discbrake rotors. In a second example, the brake devices F are rim brakedevices. In this example, the rotary bodies F1 are the rims 14C.

DESCRIPTION OF REFERENCE CHARACTERS

10) bicycle wheel assembly, 12) wheel unit, 12A) wheel unit, 14A) hubcoupling portion, 14C) rim, 14D) spoke, 16) internal thread, 18)restriction member, 18A) nut, 18B) internal thread, 20) bicycle hubunit, 20A) bicycle hub unit, 22) hub axle, 24) hub body, 24A) outercircumference, 26) first joint portion, 26A) external thread, 28) secondjoint portion, 28A) external thread, 30) large diameter portion, 30A)outer circumference, 32) first large diameter portion, 32A) first largediameter end, 32B) outer circumference, 34) second large diameterportion, 34A) second large diameter end, 34B) outer circumference, 36)tapered portion, 38) small diameter portion, 38A) outer circumference,40) rotary body coupling portion, 42) transmission portion, 44) shiftingmechanism, 52) internal thread, 54) internal thread, 56) first jointportion, 56A) external thread, 58) second joint portion, 58A) externalthread, 60) bicycle wheel assembly, 62) wheel unit, 64) hub couplingportion, 66) first tapered surface, 68) internal thread, 70) restrictionmember, 70A) nut, 70B) internal thread, 72) second tapered surface, 76)first joint portion, 76A) external thread, 78) second joint portion,78A) external thread, A) bicycle, A4) rear wheel, F) brake device, F1)rotary body, CA1) center axis, CA2) center axis, CA3) center axis

The invention claimed is:
 1. A bicycle hub unit coupled to a rotary bodyto which a brake is applied by a brake device, the bicycle hub unitcomprising: a hub body that rotates around a hub axle; and a rotary bodycoupling portion that couples the rotary body to the hub body, whereinthe hub body includes a first joint portion and a second joint portion,the first joint portion includes an external thread coupled to aninternal thread of a wheel unit, and the second joint portion is coupledto a restriction member that restricts relative rotation of the firstjoint portion and the wheel unit.
 2. The bicycle hub unit according toclaim 1, wherein the second joint portion is arranged on an outercircumference of the hub body.
 3. The bicycle hub unit according toclaim 2, wherein the second joint portion includes an external threadcoupled to an internal thread of the restriction member.
 4. The bicyclehub unit according to claim 3, wherein the external thread of the secondjoint portion differs in shape from the external thread of the firstjoint portion.
 5. The bicycle hub unit according to claim 4, wherein theexternal thread of the second joint portion differs in pitch from theexternal thread of the first joint portion.
 6. The bicycle hub unitaccording to claim 5, wherein the external thread of the second jointportion has a shorter pitch than the external thread of the first jointportion.
 7. The bicycle hub unit according to claim 4, wherein theexternal thread of the second joint portion and the external thread ofthe first joint portion are wound in opposite directions.
 8. The bicyclehub unit according to claim 7, wherein the winding direction of theexternal thread of the first joint portion is right-handed, and thewinding direction of the external thread of the second joint portion isleft-handed.
 9. The bicycle hub unit according to claim 3, wherein in adirection extending along a center axis of the hub body, a range inwhich the external thread of the first joint portion is arranged iswider than a range in which the external thread of the second jointportion is arranged.
 10. The bicycle hub unit according to claim 2,wherein the hub body further includes a large diameter portion and asmall diameter portion, and the second joint portion is arranged on anouter circumference of the small diameter portion.
 11. The bicycle hubunit according to claim 10, wherein the first joint portion is arrangedon an outer circumference of the large diameter portion.
 12. The bicyclehub unit according to claim 11, wherein the large diameter portion has asmaller outer diameter than the restriction member.
 13. The bicycle hubunit according to claim 11, wherein the large diameter portion includesa first large diameter end located toward the small diameter portion, asecond large diameter end opposite to the first large diameter end, afirst large diameter portion including the first large diameter end, anda second large diameter portion including the second large diameter end,and the first joint portion is arranged on an outer circumference of thefirst large diameter portion.
 14. The bicycle hub unit according toclaim 13, wherein the second large diameter portion includes a taperedportion, and the taper portion has an outer diameter that increases atpositions away from the first joint portion in a direction extendingalong a center axis of the hub body.
 15. The bicycle hub unit accordingto claim 1, further comprising a transmission portion that transmits atleast human driving force to the hub body.
 16. The bicycle hub unitaccording to claim 15, further comprising a shifting mechanism thatchanges speed of an input from the transmission portion and transmitsthe input to the wheel unit.
 17. The bicycle hub unit according to claim16, wherein the shifting mechanism is configured to change atransmission ratio of the transmission portion and the wheel unit. 18.The bicycle hub unit according to claim 17, wherein the shiftingmechanism has at least three transmission ratios.
 19. The bicycle hubunit according to claim 16, wherein the shifting mechanism is located ata radially inner side of the hub body.
 20. The bicycle hub unitaccording to claim 1, further comprising the hub axle.
 21. A bicyclewheel assembly comprising: the bicycle hub unit according to claim 1;the wheel unit; and the restriction member, wherein the wheel unitincludes a hub coupling portion coupled to the hub body.
 22. The bicyclewheel assembly according to claim 21, wherein the restriction memberincludes a nut, and the second joint portion includes an external threadcoupled to an internal thread of the nut.
 23. The bicycle wheel assemblyaccording to claim 22, wherein the hub coupling portion includes a firsttapered surface, the restriction member includes a second taperedsurface in contact with the first tapered surface, the first taperedsurface has a diameter that decreases toward the restriction member in adirection extending along a center axis of the hub body, and the secondtapered surface has a diameter that increases toward the hub couplingportion in the direction extending along the center axis of the hubbody.
 24. The bicycle wheel assembly according to claim 23, wherein thehub coupling portion has a center axis that is not aligned with thecenter axis of the hub body.
 25. The bicycle wheel assembly according toclaim 24, wherein the restriction member has a center axis that isaligned with the center axis of the hub body.
 26. The bicycle wheelassembly according to claim 21, wherein the wheel unit further includesa rim.
 27. The bicycle wheel assembly according to claim 26, wherein amaterial forming the rim includes at least a resin.
 28. The bicyclewheel assembly according to claim 26, wherein the wheel unit furtherincludes a spoke that connects the rim and the hub coupling portion. 29.The bicycle wheel assembly according to claim 28, wherein a materialforming the spoke includes at least a resin.
 30. The bicycle wheelassembly according to claim 21, wherein a material forming the hubcoupling portion includes at least a resin.
 31. The bicycle wheelassembly according to claim 21, wherein the bicycle wheel assembly is arear wheel.